Ridge, or top emitting mesa shaped, VCSELs are the preferred implementation over planar VCSELs because of the better current confinement and optical guiding. In the fabrication of top emitting VCSELs, the alignment of the top electrical contact to the light emitting area is very important. As an example, any internally generated light striking the electrical contact is reflected back into the laser and subsequently lost. Any misalignment of the electrical contact on the upper surface reduces the efficiency of the VCSEL. Further, the contact metal should cover the sidewall of the mesa as a reflector to reduce the optical loss and increase efficiency. Thus, any misalignment is detrimental to the VCSEL performance by blocking the intended emission and increasing the sidewall optical loss.
It is a purpose of the present invention to provide an improved method of fabricating VCSELs.
It is another purpose of the present invention to provide an improved method of fabrication VCSELs with self-aligned contacts and sidewall reflectors.
It is a further purpose of the present invention to provide an improved method of fabricating VCSELs with higher efficiency.